The move comes amid his frustration with what he sees as intolerance of conservatism in tech industry, WSJ.com reports.

The only major name in Silicon Valley to back President Donald Trump, some have called for Thiel’s removal from Facebook’s board. Chief Executive and co-founder Mark Zuckerberg has said he should stay, citing the importance of diversity of opinion at the company, Reuters has reported.

As a result, Thiel has pondered such a move.

Thiel “has grown more disaffected by what he sees as the intolerant, left-leaning politics of the San Francisco Bay Area, and increasingly pessimistic about the prospects for tech businesses amid greater risk of regulation,” people familiar with the situation told the Journal.

Late last year, Thiel sold three-quarters of his remaining stake in the social network as part of a previously established trading plan, a regulatory filing showed.

Thiel, who is a member of Facebook’s board had already sold more than $1 billion worth of its stock before the filing made in late November.

The filing said he had sold another 160,805 shares for about $29 million, leaving his holdings at 59,913 Class A shares in the company.

Thiel co-founded payment service PayPal and is known for funding the Hulk Hogan lawsuit that led to the shutdown of online news site Gawker. He became a Facebook investor in 2004 with an initial investment of $500,000 at a $5 million valuation.

When Zuckerberg took the company public in 2012, Thiel sold 16.8 million shares at the IPO for about $640 million. Later the same year, he sold roughly 20 million of his remaining 26 million shares for $400 million after the expiry of a lockup.

He hit the market once again in 2016 to sell a little less than 1 million shares for about $100 million.